Ok well I was cleaning out my garage and came across a old Guillows B-17 model kit that I was going to turn in to a RC. I got through most of the fuse and got tired of the build and it went on the shelf. I still want to do a B-17 so I decided to use the Guillows plans to build a flat foamie version. I cut out the outlines of the plane from the plans and layed them on the foam board. I am going to make it sort of 3D by adding layers to the model. I plan on adding fixed landing gear and maybe lights depending on the weight. The wing span is going to be 42". Not sure what size motors Im going to use yet. I have never built a foamie so if anyone has advice please feel free to give it. So far I have only gotten the main pieces cut.

Main pieces cut out


Here is some of the 3D effect Im going for

Looks great so far.

Hobbykings 5g outrunners turned out to be plenty of power for the B-17 I built. Its about the same size as yours, but built after fiddlers green plans and came out at slightly over 500g.
4 of those motors should be plenty to get a flat foam version flying, maybe even close to 1:1 thrust-weight-ratio.

take a look at this thread if you haven't already https://www.rcgroups.com/forums/show...&postcount=294

He's got a great design for a semi profile , nice and light but gives some 3d effect aswell as somewhere to keep your gear .

Well I got a little more done tonight. Spent most of the night removing the paper from the foam to try and lighten her up a little. All the pieces weighed in at a super 13oz. That was well above the 6oz I was going for. After removing the paper from the two outside fuses, the bottom wing brace and the elevator I got it down to 6.5oz. I could get it very light by removing the paper from the wing and center section of the fuse but I want the tail and wings strong. I also put some carbon fiber in the wings as well as the elevator. Thanks for the link and comments guys. So far I am pleased with the build. I drive a truck for a living and tend to brainstorm while driving so I have a idea of what I am going to do, but I tend to build as I go. Will post more tomorrow.

Pieces cut out with wing and elevator slots


Wing with carbon spars

Ok quick question. I added up everything and the plane should be 8-9oz with wheels, paint, hinges and what not. Add escs, servos, reciever, and batterys I think I am looking at 20oz. I was thinking of going with these motors http://www.hobbypartz.com/75m12-opti...08-1380kv.html
I like plenty of power to get out of trouble. You can always go slower. Do you think this is overkill for the weight? If so what do you suggest. I dont think the 9g motors you suggested will be enough. Also I have been looking at battery placement. With 4 motors I am thinking 2 smaller batterys mounted under the wing on each side of the fuse would work. I am looking for 4-5 flight times. Would 2 1300mah 20c work? I usually guess when it comes to this stuff and it works out put this project is a little different so I would like to get it right. Thanks for any info.

IMHO i think that motor X 4 would be overkill . I'll see if i can find something that might work there . As for the paper , take it off . Ive made the mistake on a few early builds and left it on . you can reinforce with carbon , bamboo or reinforced packing tape for a lot less weight . If i remember correctly the paper adds about 40% of the weight to a piece of foam . Build is looking really nice

Thanks Wilfor, I would appreciate the help with the motor selection. I have only built one other multi-engine plane https://www.rcgroups.com/forums/show....php?t=1202212
and it worked out pretty good. My semi common sense mind thinks that if a plane will be 20oz you would need 4 engines that can handle 7-8oz of weight each. Is that right?

Anyway, I got alot done tonight. Got the planes wing and tail sections glued on. Landing gear is on and all ailerons and elevators are cut and attached. That is where it will stay for a little while. I am going on vacation for a week so the build will be on hold. I will post pictures tommorow of the plane together.

Here are the pics of the plane together. Still need to add the tail wheel and do so clean up on the foam but its getting there.

Sorry for no response , trying to get my motor calculator working and it wont . I'll see if i can find another 1 to put some #'s in ..

Will be back from vacation tomorrow and will start back on the build tomorrow. Still need some help on a motor combo. Im looking at a finished plane around 25oz. Will be turning 3 blade 5" props. Any ideas would be appreciated.

Im hoping someone with more experience than me might comment but how about something like this guy https://www.hobbyking.com/hobbyking/s..._19g_Outrunner

Nice and light good thrust should pull it along nicely

heres another 1 in that range with free shipping http://www.rctimer.com/index.php?gOo...8&productname=

Ordered some alpha 250 motors and 10amp escs as well as servos for the build. Kind of at a holding pattern till they get here on Monday.